The invention relates to a tray.
When using medical implements which possibly might contact blood in an investigation or operation of a live body, these implements have to be sterile up to their employment. After use they are cleaned and/or desinfected, sterilised and stored. The resulting manipulation labour should be as small as possible. From DE 196 27 044 A1, a tray is known which can be inserted both into a washing device as a wash basket and into a sterilisation device as a sterilising tray. Before sterilising, the tray is closed at top and bottom by an inserted filter. To this end, pieces of a steam permeable, germs retaining filter paper are inserted into slots, and are optionally held by a clamping facility. When transporting the implements to washing, thermal desinfection and to sterilisation after use, the same need no longer to be taken by hand, but can remain within the tray. Now, it has turned out that insertion of the filters is awkward. In order to protect the filter against mechanical influences, a covering element has to be put on in some cases. Moreover, in spite of the filter papers inserted, sterile storage of implements within the tray is not ensured, because complete closure around the filter to the inner space of the tray cannot safely be realised.
Trays available on the market are known which comprise a perforated area in a central bottom region. Outside the perforated area, threaded bolts project from the bottom of the tray into its receiving region at the corner points of a rectangle. Filter paper is inserted between the threaded bolts and covers the perforated area. Subsequently, a perforated metal sheet is laid upon the filter paper aligned with the perforation of the perforated area. The threaded bolts penetrate bores of the perforated metal sheet. Now, the perforated metal sheet can be pressed against the tray bottom by nuts on the threaded bolts. By tightly clamping the filter paper, any exchange of a gas or steam between the inner space of the tray and the environment can only be effected through the filter paper. In this way, sterile storing within the tray is made possible. It has turned out, however, that the expenditure for material, production and manipulation is very high due to the additionally inserted perforated metal sheet and the awkward manner of fastening. In addition, this approach is limited to insertion of the filter paper from above onto a perforated area which is on bottom at least during insertion. This approach is not suited for a wash basket in accordance with DE 196 27 044 A1, because the implements had to be removed after washing and before the filter paper could be inserted from above.
The object of the invention consists in providing a tray at which a flat perforated area can be closed by flat filter material with small expenditure in such a way that any exchange of gas and steam between the inner space of the tray and the environment can only be effected through the filter paper. Sterile storing within the tray should be ensured over an extend period of time.
Within the scope of the present invention, it has been recognised that a seal has to be connected to the flexible, flat filter material. This seal extends preferably in a marginal area of the flexible, flat filter material along a closed line. The filter material has to be such that no micro-organisms can penetrate it. In order to arrange such a filter for achieving a closure, which ensures sterility, on a partial surface of the tray having through holes, it is sufficient that a closed sealing line is formed around the through openings and to enable clamping the seal of the filter along the parts of the tray to be interconnected by means of co-operating clamping surfaces. By the elasticity of the seal a sufficiently good closure is ensured even by small clamping pressure and even with not precisely plane clamping surfaces. Any costly screwing down a perforated plate can be omitted.
The connection of the seal and the flat filter material has the additional advantage that the filter can also be arranged at the lower side by pressing its seal into a groove and does not loosen due to gravity from the lower side. After clamping the seal between the clamping surfaces, the seal prevents any micro-organisms from entering the inner space of the tray around the filter. Due to the possibility of fastening the filter in a groove, a filter can be arranged, for example, at the inner side facing the bottom of a cover member which has a perforated area. The cover together with the filter is then put, for example, onto the closed periphery of a wash basket so that the upper front surface of the periphery presses against the seal of the filter. In this way, the inner space of the wash basket is accessible from above only through the filter. The filter is protected against any damages by the cover surface above. Analogously to the cover, a bottom having a filter inserted can be fastened to the lower front surface of the wash basket""s periphery in such a way that the filter seal is clamped between bottom and periphery. In addition, cover and bottom may be formed as identical closing members, thus, being exchangeable. In order not to obstruct the desired penetration of steam through the inserted filter, the arrangement of holes of the closing members and the wash basket are formed congruently one above another. For clamping the closing members under pressure, a clamping device is provided which acts by force optionally between cover and bottom, preferably, however, between one respective closing member and the periphery.
The filter according to the invention having a seal fastened to the flexible, flat filter material can also be employed advantageously in a tray which is used exclusively for sterilisation and, optionally, for subsequent sterile storing. A simple construction of such a sterilisation tray comprises a bottom and/or cover member having a perforated area, a peripheral region of a bottom and/or cover member engaging it positively. By putting a filter according to the invention onto the perforated area in such a way that its seal is pressed by a closed periphery of the one part against a closed partial surface extending around the perforated area of the other part, sterile closure can be ensured.
For producing the filter with a seal a linear closed seal is applied by a foaming appliance onto the flat material held by a device, which is polymerised after application, thereby providing a bond with the flat material. It would be also possible, having some more expenditure, to adhere a sealing ring onto the flat material. Optionally, the flat material cut to the desired size before applying the seal. Preferably, however, the seal is applied to a ribbon of flat material. Severing the individual filters is preferably done later. After applying the seal, preferably at least one temperature treatment is carried out in correspondence with the sealing material applied. When using a silicone foam, a first temperature treatment is carried out, for example, during at least 3, particularly 5, minutes at at least 50xc2x0 C., particularly, however, at substantially 60xc2x0 C., and optionally a second temperature treatment during at least 10, particularly 20-30, minutes at at least 120xc2x0 C., particularly, however, at substantially 140xc2x0 C. For medical applications preferably silicone foams are used, in particular those which are suitable for food and/or admitted by the Health Department.
Foamed silicone seals have a temperature, moisture and pressure resistance needed for sterilisation. This means that they reassume sufficiently quickly the initial shape after sterilisation. They maintain the desired elasticity and shape even after passing sterilisation procedures several times. Even in cases where they do not provide a tight closure because of some deformation due to temperature or pressure during sterilisation, a tight closure is ensured at least during subsequent storage. Foamed seals have a great deformation capacity and are, therefore, especially suitable for sealing clamping surfaces of high tolerance with respect to plane joining together.